Engine starting device with a starter-generator

Abstract

A starter motor is prevented from being rotated together with an engine after the start of a engine. When motor speed exceeds the cranking speed after the start of the engine, a speed judging section 36 judges that the starter motor is rotated together with the engine. A current-supply stopping section 38 commands to stop energizing a motor 3 a in response to the judge. After the electricity supply is stopped, if the rotation speed is reduced to a value close to the cranking speed, judging section 36 outputs a signal to cancel the current-supply stopping commands from the current-supply stopping section 38 . The detection of the motor speed is also continued even after the ignition, and if the speed is further increased, the speed detection is stopped. If the speed is increased to a value showing complete explosion, the speed judging section 36 switches the relays to a generator.

1. An engine starting device with a starter-generator for an internal combustion engine, wherein the starter-generator is a brushless type and is connected with the engine for starting the engine, comprising:
 speed detecting means for detecting rotation speed of the starter-generator based on voltage induced to a stationary winding of the starter-generator; 
 current-supply stopping means for stopping current-supply to the starter-generator when the rotation speed exceeds a first speed which is previously set as a start judging standard of the engine; and 
 detection stopping means for stopping a detecting operation of the speed detecting means when the rotation speed exceeds a second speed which is higher than the first speed. 
 
     
     
       2. The engine starting device for internal combustion engine according to  claim 1 , further comprising a means for releasing a current-supply stopping state which is set by the current-supply stopping means and for resuming the current-supply to the starter-generator when the rotation speed is reduced equal to or lower than a third speed which is previously set as an ignition failure judging standard after the current-supply is stopped by the current-supply stopping means. 
     
     
       3. The engine starting device for internal combustion engine according to  claim 2 , wherein the third speed is lower than the first speed. 
     
     
       4. The engine starting device for internal combustion engine according to any one of  claims 1  to  3 , wherein the starter-generator forms a rotation position signal and a rotation speed signal of a rotor based on a voltage signal which is induced to a winding to which electricity is not supplied when driving electricity is supplied to two phases among three phase stationary windings, and
 the speed detecting means detects the rotation speed of the starter-generator based on the rotation speed signal.